On 11 September 2012, the Libyan consulate in Benghazi was attacked. The US Ambassador to Libya, J Christopher Stevens, and 3 other Americans were killed in the attack. Initially it was reported that the attack was conducted by protesters angered at a controversial film produced in the United States said to insult to Prophet Muhammad and Islam. While the film may have been the inciting incident, later reports suggested that the attack had been planned and coordinated at a higher level. Reuters, citing Libyan officials, reported that the attack might have been launched by Ansar Al-Sharia. It was later reported by Wired.com's Danger Room that there were no Marine Security Guards or other Marine Assets present at the consulate in Benghazi when the attack occurred. Security was being provided by local authorities and private contractors.

The primary mission of the Marine Security Guard (MSG) is to provide internal security at designated US diplomatic and consular facilities in order to prevent the compromise of classified material vital to the national security of the United States. The secondary mission of the MSG is to provide protection for US citizens and US government property located within designated US diplomatic and consular premises during exigent circumstances (urgent temporary circumstances which require immediate aid or action). All Marine Security Guards are members of the Marine Corps Embassy Security Group (MCESG).

The Commanding Officer of MCESG reports to the Commandant of the Marine Corps, exercising command, less operational supervision, of Marines assigned to MSG detachments. MCESG Headquarters is responsible for the screening, training, assignment, administration, logistical support of Marine Corps unique items, and discipline of Marines assigned to MCESG. The Commanding Officer, MCESG also commands those Marines assigned to Headquarters, MCESG, and MCESG regional headquarters, and is the Director, MSG School. MSG School provides suitability screening and formal training for selected Marines to perform duties as MSGs at foreign Service Missions

MCESG Region Commands report to the Commanding Officer of MCESG and exercise command, less operational supervision, of Marines assigned to the MSG detachments in their respective regions. The MCESG Region Headquarters ensure the continued training, operational readiness, personnel administration, logistical support, as well as the morale, welfare, and discipline of Marines assigned for duty to MSG detachments at designated US diplomatic missions in order to support the Department of State in the protection of classified material at foreign posts. As of 2012, there were 9 separate Region Commands, numbered 1 through 9, covering Eastern Europe and Eurasia, the Near East and South Asia, East Asia and the Pacific, the Western Hemisphere - South, Western Europe and Scandinavia, Eastern and Southern Africa, Northern and Western Africa, Central Europe, and the Western Hemisphere - North.

The MSG Program was put in place in December 1948, but the Marine Corps had a long history of cooperation with the Department of State prior to that, going back to the early days of the United States of America. From the raising of the United States flag at Derna, Tripoli and the secret mission of Archibald Gillespie in California, to the 55 days at Peking, Marines have served many times on special missions as couriers, guards for embassies and legations, and to protect American citizens in unsettled areas.

The origins of the modern MSG Program began with the Foreign Service Act of 1946, which stated that the Secretary of Navy was authorized, upon the request of the Secretary of State, to assign enlisted Marines to serve as custodians under the supervision of the senior diplomatic officer at an embassy, legation, or consulate. Using this Act, the Department of State and Marine Corps entered into negotiations to establish the governing provisions for assigning MSGs overseas. These negotiations culminated in the first joint Memorandum of Agreement signed on 15 December 1948. Trained at the Department of State's Foreign Service Institute, the first MSGs departed for Tangier and Bangkok on 28 January 1949. The authority granted in the Foreign Service Act of 1946 was replaced by Title 10, United States Code 5983 and a new Memorandum of Agreement was signed on 6 March 1997. The Marine Corps also assumed the primary training responsibility for MSGs in November 1954.

By the 1990s, MSGs were organized into a Marine Security Guard Battalion. The Marine Security Guard Battalion was a tenant organization at Marine Corps Base Quantico, Virginia responsible to the Director of Operations, Headquarters, US Marine Corps. The Marine Security Guard Battalion was located in Building 2007. Selected Marines assigned to the Battalion were trained at the Marine Security Guard School and processed for duty overseas under the operational control of the Department of State as Marine Security Guards. These Marines serve at 124 embassies and consulates around the world. The Marine Security Guard Battalion also coordinated the personnel, logistics and training of these Marines worldwide. Marine Security Guards from the Battalion provided security services to selected Department of State Foreign Service posts to prevent the compromise of classified material and equipment and to provide protection for United States citizens and United States Government property. The Marine Security Guard Battalion exercised command, less operational control, of these Marines, in that it was responsible for their training, assignments, administration, logistical support, and discipline.

The Battalion's commander reported to the Director of Operations at Headquarters Marine Corps (HQMC). By the end of the 1990s, the MSG Battalion fielded over 1,000 Marines at 121 Detachments organized into 7 regional MSG companies (A through G) and located in over 105 countries. Headquarters Company and Battalion Headquarters was located aboard Marine Corps Base Quantico, Virginia. Headquarters Company consisted of approximately 100 Marines providing administrative, logistical, legal, training, and education support to the Marines around the globe. The mission of Marine Security Guard School, part of the Headquarters Company, was to select, train, and screen Marines from any Military Occupational Specialty, male or female, for MSG duty. The School was 8 weeks for detachment commanders and 6 weeks for sergeants and below. It was tough, intense, and grueling. While the 30-35 percent attrition rate was the highest of any Marine Corps school, the result was that attrition from the field was only 2-3 percent. This spoke volumes to the quality of the Marines serving on MSG duty.

The Company A Headquarters was located in Frankfurt, Germany and was responsible for 20 detachments in Eastern Europe. This company was expanding in the early 2000s, as the Department of State planned to activate MSG detachments in the states of the former Soviet Union. Sarajevo, Bosnia and Herzegovina was the latest addition to Company A. The Company B Headquarters was located in Nicosia, Cyprus and was responsible for 18 detachments in northern Africa and the Middle East. The Company C Headquarters was located in Bangkok, Thailand and was responsible for 18 detachments located in the Far East, Asia and Australia. Hanoi, Vietnam and Vladivostok, Russia were the newest additions to this company. The Company D Headquarters was located in Fort Lauderdale, Florida. Company D was the largest company with 26 detachments in Central and South America and the Caribbean. The Company E Headquarters was located, along with Company A, in Frankfurt, Germany. Company E had 16 detachments in Western Europe and Ottawa, Canada. The Company F Headquarters was located in Pretoria, South Africa and was responsible for 11 detachments in Sub-Saharan Africa. The Company G Headquarters was located in Abidjan, Cote d'Ivoire and was responsible for 12 detachments in Western Africa.

There was a joint working relationship between the MSG Battalion and the Department of State. The detachment commander reported to the battalion commander via the company commander in the administrative chain of command. The joint Memorandum of Agreement governed these relationships. In the operational chain of command, he reported to the Chief of Mission via the Regional Security Officer or Post Security Officer. Chief of Mission referred to the senior United States Diplomatic officer. This was normally an Ambassador or Consulate General. Regional Security Officers (RSO) were Diplomatic Security Special Agents. They were at the majority of missions with MSG detachments. At those posts without an RSO, one of the embassy staff was assigned the collateral duty of Post Security Officer (PSO).

MSGs would focus on the interior security of a diplomatic post's building(s). In only the most extreme emergency situations were they authorized duties exterior to the building(s) or to provide special protection to the senior diplomatic officer off of the diplomatic compound. MSGs carried a certain level of diplomatic immunity in the performance of their official duties.

"Post 1" was the name of the primary interior security post. It is normally in the lobby or main entrance of the building housing the Chief of Mission. Post 1 was the principal command station for all access control to the building. It was equipped with closed circuit televisions, radios, intrusion detection and fire alarm controls. Residing behind bulletproof glass, the MSGs could survey the personnel traffic and monitor the various security displays around the clock.

At the larger diplomatic posts, additional security positions were labeled Post 2, Post 3, etc. They might be manned 24 hours per day every day or just during normal business hours. They could have a full compliment of security displays and equipment similar to Post 1 or they could be a roving security watch after the embassy was closed

At the larger diplomatic posts, additional security positions were labeled Post 2, Post 3, etc. They might be manned 24 hours per day every day or just during normal business hours. They could have a full compliment of security displays and equipment similar to Post 1 or they could be a roving security watch after the embassy was closed

At the larger diplomatic posts, additional security positions were labeled Post 2, Post 3, etc. They might be manned 24 hours per day every day or just during normal business hours. They could have a full compliment of security displays and equipment similar to Post 1 or they could be a roving security watch after the embassy was closed

The Battalion's subordinate MSG companies were commanded by a Marine lieutenant colonel. The company headquarters normally consisted of 2 company-grade officers (first lieutenants or captains), a first sergeant, an administration chief, and 2 clerks. The company's mission was to ensure that administrative and training standards are maintained, as well as to advise the diplomatic posts in their region on the proper employment of MSGs. The company officers and first sergeant visit each MSG detachment at least 4 times every year. They not only conducted formal inspections, but observed detachment morale and met with post officials. The results of the inspections were forwarded to the Department of State.

Subordinate detachment size was based on the individual diplomatic post's requirements. The local threat level, the size and layout of the building(s), and the amount of workday business were all taken into account when determining the number and frequency of MSG security posts. The minimum detachment size was one detachment commander and 5 MSGs (referred to as a "1 and 5" or "1/5"). This allowed them to man one security post 24 hours per day, 365 days per year, while keeping the duty hours at a reasonable level so that the MSGs can conduct other routine training, internal management of the detachment, and had some time off. Diplomatic posts that required more than one security post had proportionally more MSGs. Approximately 40 percent of the Battalion's detachments were 1/5, 40 percent were between 1/6 and 1/10, and the remaining 20 percent were larger than 1/10. By the early 2000s, the largest detachment was in Cairo with 2 Staff NCOs and 28 MSGs. Detachments with more than 17 MSGs were assigned two SNCOs; one was the detachment commander and the other the assistant detachment commander.

At a diplomatic post, the detachment commander and RSO formed the Post Security Team. Their relationship was the key to the security program's success. The RSO was overall responsible for all internal and external security programs, as well as all background and criminal investigations. The detachment commander was ultimately responsible to the Chief of Mission, but normally reported to the RSO on day-to-day issues. At larger posts with several RSOs, the detachment might report to one of the Assistant RSOs.

The detachment commanders were responsible for the operation of the detachment and were considered "commanders" by the Marine Corps. This was a unique distinction because it was one of the very few times a staff noncommissioned officer (SNCO) could officially carry this title. Detachment commanders could be from the ranks of E-6 through E-9. E-8 and E-9's could only be master sergeants or master gunnery sergeants as first sergeants (E-8) and sergeant majors (E-9) could not be detachment commanders.

Unlike the individual MSGs, the detachment commanders could also be married. Detachment commanders need not have had a previous tour as an MSG, though many had. Being a detachment commander was one of 3 "special duty" assignments that an enlisted Marine generally needed in order to have a successful career. The other 2 special duties were recruiting and drill instructor. MSG duty was considered a "good deal" by the Marines in the Corps. They had an increased opportunity for promotion, lived in conditions better than most Marines in the Fleet Marine Force, and had the opportunity to live in places they likely would not if they were not an MSG.

After graduating from the School, an MSG could expect 2 15-month tours. There were some 12-month hardship tours. Detachment commanders would have 2 18-month tours. MSGs could take Continuous Overseas Tour (COT) Leave between their tours. Many returned to the United States for their COT leave, but more than a few spent it traveling overseas.

Ultimately, MSGs and detachment commanders were assigned to a detachment based on the needs of the Battalion, however, their preferences, any geographic restrictions, and input from the company commanders were factored into the assignment decision. Additionally, the Battalion used a lineal quality of life ranking of all the detachments to ensure that an MSG that had a more austere first tour would get a "better" second tour and vice versa. Finally, some MSGs were further screened and nominated to serve at selected special duty diplomatic posts.

The majority of the MSGs lived in the civilian community in a house referred to as the "Marine House." Each received their own bedroom and often their own bathroom. The detachment managed its own mess fund to ensure adequate nutrition for all. Every Marine House was equipped with exercise facilities and areas to host social events. Some houses even had a swimming pool or large lawn for organized athletics or large gatherings. The MSGs also took advantage of the Armed Forces Radio and Television Service and the Naval Motion Picture Service to watch current shows and movies.

An MSG detachment was involved in every facet of life within the American community they serve. Whether hosting social events, sponsoring local community activities, or just generally adding to the rich experience of living overseas, our MSGs were indeed "Ambassadors in Blue." There were other benefits to the presence of MSGs as well. The unplanned and unexpected evacuation of the embassies in Freetown, Sierra Leone in May 1997 and Brazzaville, Congo in June 1997 were greatly facilitated by the actions of the associated MSG detachments. Whether organizing convoys to the airport, destroying classified equipment, or providing protection to embassy personnel, the MSGs of these detachments where uniformly praised for their actions.

A new Memorandum of Agreement between the US Marine Corps and the Department of State was signed on 13 March 2008 concerning the MSGs. By the end of 2008, the Marine Security Guard Battalion has been transformed into the expanded Marine Corps Embassy Security Group. The subordinate companies of the Marine Security Guard Battalion, to which an eighth company, Company H, had been added, were inactivated. These were replaced by 9 numbered regional commands. The Marine Security Guard School remained the responsibility of the commander of the new organization.